Browsing by Author "Kumar, Vinod"
Now showing 1 - 20 of 103
Results Per Page
Sort Options
Item Open Access Acetate as a potential feedstock for the production of value-added chemicals: Metabolism and applications(Elsevier, 2021-03-26) Kim, Yeonhee; Lama, Suman; Agrawal, Deepti; Kumar, Vinod; Park, SunghoonAcetate is regarded as a promising carbon feedstock in biological production owing to its possible derivation from C1 gases such as CO, CO2 and methane. To best use of acetate, comprehensive understanding of acetate metabolisms from genes and enzymes to pathways and regulations is needed. This review aims to provide an overview on the potential of acetate as carbon feedstock for industrial biotechnology. Biochemical, microbial and biotechnological aspects of acetate metabolism are described. Especially, the current state-of-the art in the production of value-added chemicals from acetate is summarized. Challenges and future perspectives are also provided.Item Embargo Advanced steam-explosion pretreatment mediated anaerobic digestion of municipal sludge: effects on methane yield, emerging contaminants removal, and microbial community(Elsevier, 2023-09-28) Balasundaram, Gowtham; Gahlot, Pallavi; Ahmed, Banafsha; Biswas, Pinakshi; Tyagi, Vinay Kumar; Svensson, Kine; Kumar, Vinod; Kazmi, A. A.Advanced steam explosion pretreatment, i.e., the Thermal hydrolysis process (THP) is applied mainly to improve the sludge solubilization and subsequent methane yield in the downstream anaerobic digestion (AD) process. However, the potential of THP in pretreating the high solids retention time (SRT) sludges, mitigating the risk of emerging organic micropollutants and effects on anaerobic microbiome in digester remains unclear. In this study, sludge from a sequencing batch reactor (SBR) system operating at a SRT of 40 days was subjected to THP using a 5 L pilot plant at the temperature ranges of 120–180 °C for 30–120 min. The effect of THP on organics solubilization, methane yield, organic micropollutant removal, and microbial community dynamics was studied. The highest methane yield of 507 mL CH4/g VSadded and volatile solids (VS) removal of 54% were observed at 160°C- 30min THP condition, i.e., 4.1 and 2.6 times higher than the control (123 mL CH4/gVSadded, 20.7%), respectively. The experimental values of hydrolysis coefficient and methane yield have been predicted using Modified Gompertz, First order, and Logistics models. The observed values fitted well with all three models showing an R2 value between 0.96 and 1.0. THP pretreated sludges showed >80% removal of Trimethoprim, Enrofloxacin, Ciprofloxacin, and Bezafibrate. However, Carbamazepine, 17α-ethinylestradiol, and Progesterone showed recalcitrant behavior, resulting in less than 50% removal. Microbial diversity analysis showed the dominance of Proteobacteria, Firmicutes, Chloroflexi, and Bacteroidetes, collectively accounting for >70–80% of bacterial reads. They are mainly responsible for the fermentation of complex biomolecules like polysaccharides, proteins, and lipids. The THP-mediated anaerobic digestion of sludge shows better performance than the control digestion, improved methane yield, higher VS and micropollutants removal, and a diverse microbiome in the digester.Item Open Access Arabinose as an overlooked sugar for microbial bioproduction of chemical building blocks(Taylor and Francis, 2023-11-06) Kumar, Vinod; Agrawal, Deepti; Bommareddy, Rajesh Reddy; Islam, M. Ahsanul; Jacob, Samuel; Balan, Venkatesh; Singh, Vijai; Thakur, Vijay Kumar; Navani, Naveen Kumar; Scrutton, Nigel S.The circular economy is anticipated to bring a disruptive transformation in manufacturing technologies. Robust and industrial scalable microbial strains that can simultaneously assimilate and valorize multiple carbon substrates are highly desirable, as waste bioresources contain substantial amounts of renewable and fermentable carbon, which is diverse. Lignocellulosic biomass (LCB) is identified as an inexhaustible and alternative resource to reduce global dependence on oil. Glucose, xylose, and arabinose are the major monomeric sugars in LCB. However, primary research has focused on the use of glucose. On the other hand, the valorization of pentose sugars, xylose, and arabinose, has been mainly overlooked, despite possible assimilation by vast microbial communities. The present review highlights the research efforts that have explicitly proven the suitability of arabinose as the starting feedstock for producing various chemical building blocks via biological routes. It begins by analyzing the availability of various arabinose-rich biorenewable sources that can serve as potential feedstocks for biorefineries. The subsequent section outlines the current understanding of arabinose metabolism, biochemical routes prevalent in prokaryotic and eukaryotic systems, and possible products that can be derived from this sugar. Further, currently, exemplar products from arabinose, including arabitol, 2,3-butanediol, 1,2,3-butanetriol, ethanol, lactic acid, and xylitol are discussed, which have been produced by native and non-native microbial strains using metabolic engineering and genome editing tools. The final section deals with the challenges and obstacles associated with arabinose-based production, followed by concluding remarks and prospects.Item Open Access Augmented hydrolysis of acid pretreated sugarcane bagasse by PEG 6000 addition: a case study of Cellic CTec2 with recycling and reuse(Springer, 2019-11-08) Baral, Pratibha; Jain, Lavika; Kurmi, Akhilesh Kumar; Kumar, Vinod; Agrawal, DeeptiIn an integrated lignocellulosic biorefinery, the cost associated with the “cellulases” and “longer duration of cellulose hydrolysis” represents the two most important bottlenecks. Thus, to overcome these barriers, the present study aimed towards augmented hydrolysis of acid pretreated sugarcane bagasse within a short span of 16 h using Cellic CTec2 by addition of PEG 6000. Addition of this surfactant not only enhanced glucose release by twofold within stipulated time, but aided in recovery of Cellic CTec2 which was further recycled and reused for second round of saccharification. During first round of hydrolysis, when Cellic CTec2 was loaded at 25 mg protein/g cellulose content, it resulted in 76.24 ± 2.18% saccharification with a protein recovery of 58.4 ± 1.09%. Filtration through 50KDa PES membrane retained ~ 89% protein in 4.5-fold concentrated form and leads to simultaneous fractionation of ~ 70% glucose in the permeate. Later, the saccharification potential of recycled Cellic CTec2 was assessed for the second round of saccharification using two different approaches. Unfortified enzyme effectively hydrolysed 67% cellulose, whereas 72% glucose release was observed with Cellic CTec2 fortified with 25% fresh protein top-up. Incorporating the use of the recycled enzyme in two-stage hydrolysis could effectively reduce the Cellic CTec2 loading from 25 to 16.8 mg protein/g cellulose. Furthermore, 80% ethanol conversion efficiencies were achieved when glucose-rich permeate obtained after the first and second rounds of saccharification were evaluated using Saccharomyces cerevisiae MTCC 180.Item Open Access Bioactive compounds of edible fruits with their anti-aging properties: a comprehensive review to prolong human life(MDPI, 2020-11-13) Dhalaria, Rajni; Verma, Rachna; Kumar, Dinesh; Puri, Sunil; Tapwal, Ashwani; Kumar, Vinod; Nepovimova, Eugenie; Kuca, KamilAging is a complicated biological process in which functional and structural alterations in a living organism take place over time. Reactive oxygen species is one of the main factors responsible for aging and is associated with several chronic pathologies. The relationship between aging and diet is quite interesting and has attained worldwide attention. Healthy food, in addition to dietary antioxidants, are required to delay the process of aging and improve the quality of life. Many healthy foods such as fruits are a good source of dietary nutrients and natural bioactive compounds which have antioxidant properties and are involved in preventing aging and other age-related disorders. Health benefits linked with healthy consumption of fruit have drawn increased interest. A significant number of studies have documented the advantages of fruit intake, as it suppresses free-radical development that further reduces the oxidative stress created in the body and protects against several types of diseases such as cancer, type 2 diabetes, inflammatory disorders, and other cardiovascular diseases that ultimately prevent aging. In addition, fruits have numerous other properties like anti-inflammatory, anti-cancerous, anti-diabetic, neuroprotective, and have health-promoting effects. Mechanisms of various bioactive compounds that aids in preventing various diseases and increases longevity are also described. This manuscript provides a summary of various bioactive components present in fruits along with their health-promoting and antiaging properties.Item Open Access Bioengineered bioreactors: a review on enhancing biomethane and biohydrogen production by CFD modeling(Taylor & Francis, 2021-09-17) Saini, Anand Kumar; Radu, Tanja; Paritosh, Kunwar; Kumar, Vinod; Pareek, Nidhi; Tripathi, Dharmendra; Vivekanand, VivekanandComputational fluid dynamics (CFD) is numerical strategy developed for simulating the behavior of liquid and gas flow. CFD may be applied starting from aerospace, engine design, vehicle aerodynamics, power plants and chemical industries for analyzing and solving relevant system design and process issues. Biogas produced during anaerobic digestion (AD) is sustainable and renewable alternative to fossil fuels. AD may improve the controlled production of biogas and offers significant environmental benefits. This review focuses on research outcomes relevant for enhanced biogas production by exploring the possible applications of CFD in AD technology. CFD-related research performed in AD conditions in order to improve mixing performance, reduce power consumption, and understand the effects of total solid (TS) concentrations on flow behavior have been discussed. In addition, the use of AD for bio-hydrogen production, wastewater treatment, and sludge treatment are looked in. This review also identifies novel areas for AD technology advancement where there is potential for economic improvement in renewable energy production. Finally, future research needs have been identified, focusing on the opportunities to integrate conceptual and mathematical models for advancing CFD simulations for bioenergy.Item Open Access Biological production and recovery of 2,3-butanediol using arabinose from sugar beet pulp by Enterobacter ludwigii(Elsevier, 2022-04-21) Narisetty, Vivek; Narisetty, Sudheera; Jacob, Samuel; Kumar, Deepak; Leeke, Gary A.; Chandel, Anuj Kumar; Singh, Vijai; Srivastava, Vimal Chandra; Kumar, VinodSugar beet pulp (SBP) is a major byproduct from the sugar industries and consists of >20% w/w arabinose. The current work evaluated the potential of Enterobacter ludwigii assimilating pure arabinose and arabinose rich hydrolysate from SBP pellets for 2,3-butanediol (BDO) production. The hydrolysate was obtained through dilute acid pretreatment (DAP) with sulphuric acid. The process was optimized for acid and solid loading to obtain a hydrolysate free from furan derivatives. The effect of different levels of substrate (10–60 g/L) using pure arabinose was conducted in shake flask experiments, followed by co-fermentation with small amounts of glucose and SBP hydrolysate. After flask cultivations, BDO fermentations were carried-out in a bench-top bioreactor in batch and fed-batch modes using pure arabinose as well as SBP hydrolysate. The fed-batch culture led to BDO production of 42.9 and 35.5 g/L from pure arabinose and SBP hydrolysate with conversion yields of 0.31 and 0.29 g/g, respectively. Finally, BDO accumulated on pure arabinose and SBP hydrolysate were recovered using an aqueous two-phase extraction system. The recovery yield of BDO accumulated on arabinose and hydrolysate was ∼97%. The work demonstrated the feasibility of using SBP as a suitable feedstock for manufacturing BDO.Item Open Access Bioprocessing of fermentable sugars derived from water hyacinth into microbial lipids and single cell proteins by oleaginous yeast Rhodosporidium toruloides NCIM 3547(Springer, 2021-10-09) Alankar, Senthilnathan Sri Laxma; Sajesh, Nithianandam; Rastogi, Shrestha; Sakhuja, Simar; Rajeswari, Gunasekaran; Kumar, Vinod; Chandel, Anuj Kumar; Jacob, SamuelIn this study, we employed microwave-acid pretreatment for water hyacinth (WH) to obtain liquid hydrolysate that contains sugars derived from holocellulosic components of biomass for further oleaginous yeast fermentation. In order to remove the inhibitors such as furans after acid treatment, detoxification of hydrolysate was done and we compared the efficiency of this step with non-detoxified hydrolysate towards capability of the Rhodosporidium toruloides NCIM 3547 (an oleaginous yeast) to produce microbial lipid and single cell protein. The results indicated that the reducing sugar concentration was found to be higher in non-detoxified hydrolysate (65.41 g/L) than detoxified one (59.18 g/L). When the non-detoxified liquid hydrolysate was supplemented with yeast extract as a complex organic source for R. toruloides, resulted in a maximum lipid yield of about 0.813 ± 0.041 (g/g) and 53.60 ± 2.68 (g/g) of single cell protein content with 0.038 g/L/d of protein productivity. Two kinetic models, hybrid Logistic-Monod and Luedeking-Piret, were employed to assess the microbial growth and the substrate utilization that were found to be in well agreement with the experimental data with a coefficient of determination (R2) value ranging from 0.95 to 0.99 thereby demonstrating the efficiency of the hydrolysate supplemented media. Furthermore, GC-MS analysis of transesterified lipids revealed the presence of various FAME (fatty acid methyl esters) and also the presence of increased levels of total saturated fatty acids (35.03%) advocates its high potential in biodiesel production. This study demonstrates the feasibility of sustainable valorization of WH-derived liquid hydrolysate towards a greener biorefinery framework.Item Open Access Bioproduction of succinic acid from xylose by engineered Yarrowia lipolytica without pH control(BMC - Springer Nature, 2020-06-27) Prabhu, Ashish Ashok; Ledesma-Amaro, Rodrigo; Lin, Carol Sze Ki; Coulon, Frederic; Thakur, Vijay Kumar; Kumar, VinodBackground Xylose is the most prevalent sugar available in hemicellulose fraction of lignocellulosic biomass (LCB) and of great interest for the green economy. Unfortunately, most of the cell factories cannot inherently metabolize xylose as sole carbon source. Yarrowia lipolytica is a non-conventional yeast that produces industrially important metabolites. The yeast is able to metabolize a large variety of substrates including both hydrophilic and hydrophobic carbon sources. However, Y. lipolytica lacks effective metabolic pathway for xylose uptake and only scarce information is available on utilization of xylose. For the economica feasibility of LCB-based biorefineries, effective utilization of both pentose and hexose sugars is obligatory. Results In the present study, succinic acid (SA) production from xylose by Y. lipolytica was examined. To this end, Y. lipolytica PSA02004 strain was engineered by overexpressing pentose pathway cassette comprising xylose reductase (XR), xylitol dehydrogenase (XDH) and xylulose kinase (XK) gene. The recombinant strain exhibited a robust growth on xylose as sole carbon source and produced substantial amount of SA. The inhibition of cell growth and SA formation was observed above 60 g/L xylose concentration. The batch cultivation of the recombinant strain in a bioreactor resulted in a maximum biomass concentration of 7.3 g/L and SA titer of 11.2 g/L with the yield of 0.19 g/g. Similar results in terms of cell growth and SA production were obtained with xylose-rich hydrolysate derived from sugarcane bagasse. The fed-batch fermentation yielded biomass concentration of 11.8 g/L (OD600: 56.1) and SA titer of 22.3 g/L with a gradual decrease in pH below 4.0. Acetic acid was obtained as a main by-product in all the fermentations. Conclusion The recombinant strain displayed potential for bioconversion of xylose to SA. Further, this study provided a new insight on conversion of lignocellulosic biomass into value-added products. To the best of our knowledge, this is the first study on SA production by Y. lipolytica using xylose as a sole carbon source.Item Open Access Bioremediation of petroleum hydrocarbons by vermicomposting process bioaugmentated with indigenous bacterial consortium isolated from petroleum oily sludge(Elsevier, 2020-04-25) Koolivand, Ali; Saeedi, Reza; Coulon, Frederic; Kumar, Vinod; Villaseñor, José; Asghari, Fatemeh; Hesampoor, FaezehFinding a sound ecological-based approach for the removal of petroleum hydrocarbons (PHCs) from petroleum oily sludge (POS) generated in oil refinery plants is still a challenge. This study investigated the removal of total petroleum hydrocarbons (TPHs) using bioaugmentated composting (BC) by hydrocarbon-degrading bacteria (HDB) and vermicomposting (VC) by Eisenia fetida, individually and in combination (BCVC). After isolating two native bacterial strains from POS prepared from an oil refinery plant in Iran, the degradation capability of their consortium was initially assessed in mineral Bushnell-Haas medium (MBHM). Then, the biodegradation rates of POS in the BC, VC, and BCVC treatments containing different concentrations of TPHs (5, 10, and 20 g/kg) were determined by measuring TPHs before and after the biodegradation. The results showed that the consortium degraded 20–62% of TPHs contents of Kerosene (1–5%) in the MBHM after 7 days. After 12 weeks, the TPHs removal percentages in the BC, VC, and BCVC treatments were respectively found to be 81–83, 31–49, and 85–91 indicating the synergistic effect of bacteria and worms in bioremediation of POS. The PHCs biodegradation in the BC, VC, and BCVC experiments was fitted to 1st order model kinetics. The results of toxicity tests indicated that the values of the no observed lethal concentration (NOLC) and median lethal concentration (LC50) of TPHs were 2–5 and 14.64 g/kg, respectively after 28 days of earthworm exposure. Morphological impairments such as swelling, coiling, and curling were observed when TPHs concentration was even lower than NOLC. The study verified the effectiveness of vermicomposting bioaugmentated with the indigenous bacterial consortium for POS bioremediation.Item Open Access Biovalorisation of crude glycerol and xylose into xylitol by oleaginous yeast Yarrowia lipolytica(BMC (part of Springer Nature), 2020-06-03) Prabhu, Vinayak Ashok; Thomas, Dominic J.; Ledesma-Amaro, Rodrigo; Leeke, Gary A.; Medina, Angel; Verheecke-Vaessen, Carol; Coulon, Frederic; Agrawal, Deepti; Kumar, VinodBackground Xylitol is a commercially important chemical with multiple applications in the food and pharmaceutical industries. According to the US Department of Energy, xylitol is one of the top twelve platform chemicals that can be produced from biomass. The chemical method for xylitol synthesis is however, expensive and energy intensive. In contrast, the biological route using microbial cell factories offers a potential cost-effective alternative process. The bioprocess occurs under ambient conditions and makes use of biocatalysts and biomass which can be sourced from renewable carbon originating from a variety of cheap waste feedstocks. Result In this study, biotransformation of xylose to xylitol was investigated using Yarrowia lipolytica, an oleaginous yeast which was firstly grown on a glycerol/glucose for screening of co-substrate, followed by media optimisation in shake flask, scale up in bioreactor and downstream processing of xylitol. A two-step medium optimization was employed using central composite design and artificial neural network coupled with genetic algorithm. The yeast amassed a concentration of 53.2 g/L xylitol using pure glycerol (PG) and xylose with a bioconversion yield of 0.97 g/g. Similar results were obtained when PG was substituted with crude glycerol (CG) from the biodiesel industry (titer: 50.5 g/L; yield: 0.92 g/g). Even when xylose from sugarcane bagasse hydrolysate was used as opposed to pure xylose, a xylitol yield of 0.54 g/g was achieved. Xylitol was successfully crystallized from PG/xylose and CG/xylose fermentation broths with a recovery of 39.5 and 35.3%, respectively. Conclusion To the best of the author’s knowledge, this study demonstrates for the first time the potential of using Y. lipolytica as a microbial cell factory for xylitol synthesis from inexpensive feedstocks. The results obtained are competitive with other xylitol producing organisms.Item Open Access Bread waste valorization: a review of sustainability aspects and challenges(Frontiers, 2024-02-05) Hafyan, Rendra Hakim; Mohanarajan, Jasmithaa; Uppal, Manaal; Kumar, Vinod; Narisetty, Vivek; Maity, Sunil K.; Sadhukhan, Jhuma; Gadkari, SiddharthBread waste (BW) poses a significant environmental and economic challenge in the United Kingdom (UK), where an estimated 20 million slices of bread are wasted daily. BW contains polysaccharides with great potential for its valorization into building block chemicals. While BW valorization holds tremendous promise, it is an emerging field with low technology readiness levels (TRLs), necessitating careful consideration of sustainability and commercial-scale utilization. This review offers a comprehensive assessment of the sustainability aspects of BW valorization, encompassing economic, environmental, and social factors. The primary objective of this review article is to enhance our understanding of the potential benefits and challenges associated with this approach. Incorporating circular bioeconomy principles into BW valorization is crucial for addressing global issues stemming from food waste and environmental degradation. The review investigates the role of BW-based biorefineries in promoting the circular bioeconomy concept. This study concludes by discussing the challenges and opportunities of BW valorization and waste reduction, along with proposing potential strategies to tackle these challenges.Item Open Access Bread waste – a potential feedstock for sustainable circular biorefineries(Elsevier, 2022-12-21) Kumar, Vinod; Brancoli, Pedro; Narisetty, Vivek; Wallace, Stephen; Charalampopoulos, Dimitris; Kumar Dubey, Brajesh; Kumar, Gopalakrishnan; Bhatnagar, Amit; Bhatia, Shashi Kant; Taherzadeh, Mohammad J.The management of staggering volume of food waste generated (∼1.3 billion tons) is a serious challenge. The readily available untapped food waste can be promising feedstock for setting up biorefineries and one good example is bread waste (BW). The current review emphasis on capability of BW as feedstock for sustainable production of platform and commercially important chemicals. It describes the availability of BW (>100 million tons) to serve as a feedstock for sustainable biorefineries followed by examples of platform chemicals which have been produced using BW including ethanol, lactic acid, succinic acid and 2,3-butanediol through biological route. The BW-based production of these metabolites is compared against 1G and 2G (lignocellulosic biomass) feedstocks. The review also discusses logistic and supply chain challenges associated with use of BW as feedstock. Towards the end, it is concluded with a discussion on life cycle analysis of BW-based production and comparison with other feedstocks.Item Open Access Carbon emissions and decarbonisation: the role and relevance of fermentation industry in chemical sector(Elsevier, 2023-10-07) Agrawal, Deepti; Awani, Kelvin; Nabavi, Seyed Ali; Balan, Venkatesh; Jin, Mingjie; Aminabhavi, Tejraj M.; Dubey, Kashyap Kumar; Kumar, VinodFermentation industry is emerging as sustainable technological alternative to cater the production of various chemical building blocks which are commercially manufactured by petrochemical route. The primary reason for this major transition is global commitment towards decarbonisation of chemical sector, as their conventional fossil-based routes pose serious environmental threat. For instance, in 2022, the direct carbon dioxide (CO2) emission during synthesis of primary chemicals accounted for ∼ 920 Mt. CO2 is one of the prominent greenhouse gases (GHG’s), contributing majorly towards global warming effect and drastic climate change. Fermentation industry largely thrives on exploiting fermentable and organic carbon derived from edible and/or non-edible biomass and transforming them to valorised products using microbial cell factories. Therefore, the production of bio-based chemicals via this route is often associated with low or zero-carbon footprint, resulting in either carbon neutral or carbon negative products. This review focuses on different types of fermentative processes and their impact on carbon release and decarbonisation. It further discusses the relevance and contribution of fermentation industry as well as biological processes to provide a sustainable solution towards decarbonisation of chemical sector. Further, it showcases the advantages of some commercial proven and/or pipeline bio-based products over their conventional competitor fossil-based products, especially from an environmental viewpoint. Finally, advantages of biogenic CO2 from fermentation industry over other sources and CO2 removal from fermentation as a platform for carbon offsetting are covered.Item Open Access Cellulose-based smart materials: Novel synthesis techniques, properties, and applications in energy storage and conversion devices(Wiley, 2024-05-25) Bishnoi, Pariksha; Siwal, Samarjeet Singh; Kumar, Vinod; Thakur, Vijay KumarThere has been a significant scope toward the cutting-edge investigations in hierarchical carbon nanostructured electrodes originating from cellulosic materials, such as cellulose nanofibers, available from natural cellulose and bacterial cellulose. Elements of energy storage systems (ESSs) are typically established upon inorganic/metal mixtures, carbonaceous implications, and petroleum-derived hydrocarbon chemicals. However, these conventional substances may need help fulfilling the ever-increasing needs of ESSs. Nanocellulose has grown significantly as an impressive 1D element due to its natural availability, eco-friendliness, recyclability, structural identity, simple transformation, and dimensional durability. Here, in this review article, we have discussed the role and overview of cellulose-based hydrogels in ESSs. Additionally, the extraction sources and solvents used for dissolution have been discussed in detail. Finally, the properties (such as self-healing, transparency, strength and swelling behavior), and applications (such as flexible batteries, fuel cells, solar cells, flexible supercapacitors and carbon-based derived from cellulose) in energy storage devices and conclusion with existing challenges have been updated with recent findings.Item Open Access Comprehensive review on biotechnological production of hyaluronic acid: status, innovation, market and applications(Taylor and Francis, 2022-04-18) Ucm, Ruschoni; Aema, Mera; Lhb, Zamudio; Kumar, Vinod; Taherzadeh, Mohammad J.; Garlapati, Vijay KumarThe growing, existing demand for low-cost and high-quality hyaluronic acid (HA) needs an outlook of different possible production strategies from renewable resources with the reduced possibility of cross-infections. Recently, the possibility of producing HA from harmless microorganisms appeared, which offers the opportunity to make HA more economical, without raw material limitations, and environmentally friendly. HA production is mainly reported with Lancefield Streptococci A and C, particularly from S. equi and S. zooepidemicus. Various modes of fermentation such as batch, repeated batch, fed-batch, and continuous culture have been investigated to optimize HA production, particularly from S. zooepidemicus, obtaining a HA yield of 2.5 g L−1 – 7.0 g L−1. Among the different utilized DSP approaches of HA production, recovery with cold ethanol (4°C) and cetylpyridinium chloride is the ideal strategy for lab-scale HA production. On the industrial scale, besides using isopropanol, filtration (0.22 um), ultrafiltration (100 kDa), and activated carbon absorption are employed to obtain HA of low molecular weight and additional ultrafiltration to purify HA of higher MW. Even though mature technologies have already been developed for the industrial production of HA, the projections of increased sales volume and the expansion of application possibilities require new processes to obtain HA with higher productivity, purity, and specific molecular weights. In this review, we have put forth the progress of HA technological research by discussing the microbial biosynthetic aspects, fermentation and downstream strategies, industrial-scale scenarios of HA, and the prospects of HA production to meet the current and ongoing market demands.Item Open Access A concerted enzymatic de-structuring of lignocellulosic materials using a compost-derived microbial consortia favoring the consolidated pretreatment and bio-saccharification(Elsevier, 2024-01-13) Rajeswari, Gunasekaran; Kumar, Vinod; Jacob, SamuelThe robustness of microbial consortia isolated from compost habitat encompasses the complementary metabolism that aids in consolidated bioprocessing (CBP) of lignocellulosic biomass (LCB) by division of labor across the symbionts. Composting of organic waste is deemed to be an efficient way of carbon recycling, where the syntrophic microbial population exerts a concerted action of lignin and polysaccharide (hemicellulose and cellulose) component of plant biomass. The potential of this interrelated microorganism could be enhanced through adaptive laboratory evolution (ALE) with LCB for its desired functional capabilities. Therefore, in this study, microbial symbionts derived from organic compost was enriched on saw dust (SD) (woody biomass), aloe vera leaf rind (AVLR) (agro-industrial waste) and commercial filter paper (FP) (pure cellulose) through ALE under different conditions. Later, the efficacy of enriched consortium (EC) on consolidated pretreatment and bio-saccharification was determined based on substrate degradation, endo-enzymes profiling and fermentable sugar yield. Among the treatment sets, AVLR biomass treated with EC-5 has resulted in the higher degradation rate of lignin (47.01 ± 0.66%, w/w) and polysaccharides (45.87 ± 1.82%, w/w) with a total sugar yield of about 60.01 ± 4.24 mg/g. In addition, the extent of structural disintegration of substrate after EC-treatment was clearly deciphered by FTIR and XRD analysis. And the factors of Pearson correlation matrix reinforces the potency of EC-5 by exhibiting a strong positive correlation between AVLR degradation and the sugar release. Thus, a consortium based CBP could promote the feasibility of establishing a sustainable second generation biorefinery framework.Item Open Access Cost reduction approaches for fermentable sugar production from sugarcane bagasse and its impact on techno-economics and the environment(Springer, 2021-05-18) Baral, Pratibha; Munagala, Meghana; Shastri, Yogendra; Kumar, Vinod; Agrawal, DeeptiIn an enzymatically driven lignocellulosic biorefinery, pretreatment and hydrolysis modules are the two most significant cost contributors for obtaining high gravity sugar solutions. The present study aimed to reduce the use of alkali and Cellic CTec2 during the bioprocessing of sugarcane bagasse (SCB). Later its impact on the overall process economics and the environment was evaluated. During pretreatment, solid loading of 15% (w/w) and use of 2% (w/v) sodium hydroxide at 121 °C for 30 min emerged as an optimum strategy. It resulted in > 65% delignification of SCB, retaining ≥ 90% and 65% of glucan and xylan fraction, respectively, in the pretreated biomass. Two approaches were evaluated in parallel to minimize the requirement of this commercial cellulase enzyme blend. The first strategy involved its partial replacement with an in-house enzyme cocktail by blending. The second route was performing hydrolysis with reduced loadings of cellulase enzyme blend above its optimum temperature, which gave more promising results. Hydrolysis of 20% alkali pretreated SCB with cellulase enzyme blend dosed at 15 mg protein g−1 glucan led to 84.13 ± 1 and 83.5 ± 2.3% glucan and xylan conversion yields respectively in 48 h at 52.5 °C. The filtrate and wash fraction contained ≥ 165 and ≥ 65 g L−1 sugar monomers representing glucose and xylose. However, in both the fractions > 75%, sugar accounted for glucose. The techno-economic analysis revealed that the sugar production cost from SCB was 1.32 US$/kg, with the optimized bioprocess. Environmental impact study showed that the process contributed to 1.57 kg CO2 eq in terms of climate change.Item Open Access Critical review of nanopillar-based mechanobactericidal systems(American Chemical Society, 2022-01-05) Hawi, Sara; Goel, Saurav; Kumar, Vinod; Pearce, Oliver; Nishio Ayre, Wayne; Ivanova, Elena P.The rise of multidrug-resistant bacteria is the biggest threat to human health globally, as described by the World Health Organization. Mechanobactericidal surfaces provide a sustainable approach to addressing this concern by eradicating pathogens, especially bacteria, “right-at-the-point” of contacting the surface. However, the lack of a “design to manufacture” approach due to our limited understanding of the mechanobactericidal mechanism has impeded engineering optimization to develop scalable exploitation routes in various healthcare applications. It can be argued that the reason, most particularly, is the limitations and uncertainties associated with the current instrumentation and simulation capabilities, which has led to several streams of test protocols. This review highlights the current understanding on the mechanobactericidal mechanisms in light of the contributing factors and various techniques that are used to postulate these mechanisms. The review offers a critique on the variations observed on how nanostructured surfaces found in the literature have been evaluated such that the test protocols and outcomes are incomparable. The review also shows a strong need for developing more accurate models of a bacterium because the currently reported experimental data are insufficient to develop bacterial material models (constitutive equations). The review also alludes to the scarcity of direct experimental evidence of the mechanobactericidal mechanism, suggesting a strong need for further in situ monitoring as a future research direction.Item Open Access Current state of the art biotechnological strategies for conversion of watermelon wastes residues to biopolymers production: a review(Elsevier, 2021-12-14) Awasthi, Mukesh Kumar; Kumar, Vinay; Yadav, Vivek; Sarsaiya, Surendra; Awasthi, Sanjeev Kumar; Sindhu, Raveendran; Binod, Parameswaran; Kumar, Vinod; Pandey, Ashok; Zhang, ZengqiangPoly-3-hydroxyalkanoates (PHA) are biodegradable and compostable polyesters. This review is aimed to provide a unique approach that can help think tanks to frame strategies aiming for clean technology by utilizing cutting edge biotechnological advances to convert fruit and vegetable waste to biopolymer. A PHA manufacturing method based on watermelon waste residue that does not require extensive pretreatment provides a more environmentally friendly and sustainable approach that utilizes an agricultural waste stream. Incorporating fruit processing industry by-products and water, and other resource conservation methods would not only make the manufacturing of microbial bio-plastics like PHA more eco-friendly, but will also help our sector transition to a bioeconomy with circular product streams. The final and most critical element of this review is an in-depth examination of the several hazards inherent in PHA manufacturing.